---
title: 使用 kubeadm 创建一个高可用 etcd 集群
content_template: templates/task
weight: 60
--- 
<!--
---
reviewers:
- sig-cluster-lifecycle
title: Set up a High Availability etcd cluster with kubeadm
content_template: templates/task
weight: 60
---
-->

{{% capture overview %}}

<!--
Kubeadm defaults to running a single member etcd cluster in a static pod managed
by the kubelet on the control plane node. This is not a high availability setup
as the etcd cluster contains only one member and cannot sustain any members
becoming unavailable. This task walks through the process of creating a high
availability etcd cluster of three members that can be used as an external etcd
when using kubeadm to set up a kubernetes cluster. 
-->
默认情况下，kubeadm 运行单成员的 etcd 集群，该集群由控制面节点上的 kubelet 以静态 Pod 的方式进行管理。由于 etcd 集群只包含一个成员且不能在任一成员不可用时保持运行，所以这不是一种高可用设置。本任务，将告诉您如何在使用 kubeadm 创建一个 kubernetes 集群时创建一个外部 etcd：有三个成员的高可用 etcd 集群。

{{% /capture %}}

{{% capture prerequisites %}}

<!--
* Three hosts that can talk to each other over ports 2379 and 2380. This document assumes these default ports. However, they are configurable through the kubeadm config file. 
-->
* 三个可以通过 2379 和 2380 端口相互通信的主机。本文档使用这些作为默认端口。不过，它们可以通过 kubeadm 的配置文件进行自定义。

<!--
* Each host must [have docker, kubelet, and kubeadm installed][toolbox]. 
-->
* 每个主机必须 [安装有 docker、kubelet 和 kubeadm][工具箱]。

<!--
* Some infrastructure to copy files between hosts. For example `ssh` and `scp` can satisfy this requirement. 
-->
* 一些可以用来在主机间复制文件的基础设施。例如 `ssh` 和 `scp` 就可以满足需求。

<!--
[toolbox]: /docs/setup/independent/install-kubeadm/ 
-->
[工具箱]: /docs/setup/independent/install-kubeadm/

{{% /capture %}}

{{% capture steps %}}

<!--
## Setting up the cluster 
-->
## 建立集群

<!--
The general approach is to generate all certs on one node and only distribute the *necessary* files to the other nodes. 
-->
一般来说，是在一个节点上生成所有证书并且只分发这些*必要*的文件到其它节点上。

{{< note >}}
<!--
kubeadm contains all the necessary crytographic machinery to generate the certificates described below; no other cryptographic tooling is required for this example. 
-->
kubeadm 包含生成下述证书所需的所有必要的密码学工具；在这个例子中，不需要其他加密工具。
{{< /note >}}

<!--
1. Configure the kubelet to be a service manager for etcd.

    Running etcd is simpler than running kubernetes so you must override the
    kubeadm-provided kubelet unit file by creating a new one with a higher
    precedence. 
-->
1. 将 kubelet 配置为 etcd 的服务管理器。

    运行 etcd 比运行 kubernetes 更简单，因此您必须通过创建具有更高优先级的新文件来覆盖 kubeadm 提供的 kubelet 单元文件。

    ```sh
    cat << EOF > /etc/systemd/system/kubelet.service.d/20-etcd-service-manager.conf
    [Service]
    ExecStart=
    ExecStart=/usr/bin/kubelet --address=127.0.0.1 --pod-manifest-path=/etc/kubernetes/manifests --allow-privileged=true
    Restart=always
    EOF

    systemctl daemon-reload
    systemctl restart kubelet
    ```

    <!--
    1.Create configuration files for kubeadm.
    
        Generate one kubeadm configuration file for each host that will have an etcd
        member running on it using the following script. 
    -->

1. 为 kubeadm 创建配置文件。

    使用以下脚本为每个将要运行 etcd 成员的主机生成一个 kubeadm 配置文件。
    
    <!--
    ```sh
    # Update HOST0, HOST1, and HOST2 with the IPs or resolvable names of your hosts
    export HOST0=10.0.0.6
    export HOST1=10.0.0.7
    export HOST2=10.0.0.8

    # Create temp directories to store files that will end up on other hosts.
    mkdir -p /tmp/${HOST0}/ /tmp/${HOST1}/ /tmp/${HOST2}/

    ETCDHOSTS=(${HOST0} ${HOST1} ${HOST2})
    NAMES=("infra0" "infra1" "infra2")

    for i in "${!ETCDHOSTS[@]}"; do
    HOST=${ETCDHOSTS[$i]}
    NAME=${NAMES[$i]}
    cat << EOF > /tmp/${HOST}/kubeadmcfg.yaml
    apiVersion: "kubeadm.k8s.io/v1alpha3"
    kind: ClusterConfiguration
    etcd:
        local:
            serverCertSANs:
            - "${HOST}"
            peerCertSANs:
            - "${HOST}"
            extraArgs:
                initial-cluster: infra0=https://${ETCDHOSTS[0]}:2380,infra1=https://${ETCDHOSTS[1]}:2380,infra2=https://${ETCDHOSTS[2]}:2380
                initial-cluster-state: new
                name: ${NAME}
                listen-peer-urls: https://${HOST}:2380
                listen-client-urls: https://${HOST}:2379
                advertise-client-urls: https://${HOST}:2379
                initial-advertise-peer-urls: https://${HOST}:2380
    EOF
    done
    ``` 
    -->
    ```sh
    # 使用 IP 或可解析的主机名替换 HOST0、HOST1 和 HOST2
    export HOST0=10.0.0.6
    export HOST1=10.0.0.7
    export HOST2=10.0.0.8
    
    # 创建临时目录来存储将被分发到其它主机上的文件
    mkdir -p /tmp/${HOST0}/ /tmp/${HOST1}/ /tmp/${HOST2}/
    
    ETCDHOSTS=(${HOST0} ${HOST1} ${HOST2})
    NAMES=("infra0" "infra1" "infra2")
    
    for i in "${!ETCDHOSTS[@]}"; do
    HOST=${ETCDHOSTS[$i]}
    NAME=${NAMES[$i]}
    cat << EOF > /tmp/${HOST}/kubeadmcfg.yaml
    apiVersion: "kubeadm.k8s.io/v1alpha3"
    kind: ClusterConfiguration
    etcd:
        local:
            serverCertSANs:
            - "${HOST}"
            peerCertSANs:
            - "${HOST}"
            extraArgs:
                initial-cluster: infra0=https://${ETCDHOSTS[0]}:2380,infra1=https://${ETCDHOSTS[1]}:2380,infra2=https://${ETCDHOSTS[2]}:2380
                initial-cluster-state: new
                name: ${NAME}
                listen-peer-urls: https://${HOST}:2380
                listen-client-urls: https://${HOST}:2379
                advertise-client-urls: https://${HOST}:2379
                initial-advertise-peer-urls: https://${HOST}:2380
    EOF
    done
    ```

    <!--
    1.Generate the certificate authority

        If you already have a CA then the only action that is copying the CA's `crt` and
        `key` file to `/etc/kubernetes/pki/etcd/ca.crt` and
        `/etc/kubernetes/pki/etcd/ca.key`. After those files have been copied,
        proceed to the next step, "Create certificates for each member". 
    -->
1. 生成证书颁发机构

    如果您已经拥有 CA，那么唯一的操作是复制 CA 的 `crt` 和 `key` 文件到 `etc/kubernetes/pki/etcd/ca.crt` 和 `/etc/kubernetes/pki/etcd/ca.key`。复制完这些文件后继续下一步，“为每个成员创建证书”。

    <!--
    If you do not already have a CA then run this command on `$HOST0` (where you generated the configuration files for kubeadm). 
    -->
    如果您还没有 CA，则在 `$HOST0`（您为 kubeadm 生成配置文件的位置）上运行此命令。

    ```
    kubeadm alpha phase certs etcd-ca
    ```

    <!--
    This creates two files 
    -->
    创建了如下两个文件

    - `/etc/kubernetes/pki/etcd/ca.crt`
    - `/etc/kubernetes/pki/etcd/ca.key`

    <!--
    1. Create certificates for each member 
    -->
1. 为每个成员创建证书

    <!--
    ```sh
    kubeadm alpha phase certs etcd-server --config=/tmp/${HOST2}/kubeadmcfg.yaml
    kubeadm alpha phase certs etcd-peer --config=/tmp/${HOST2}/kubeadmcfg.yaml
    kubeadm alpha phase certs etcd-healthcheck-client --config=/tmp/${HOST2}/kubeadmcfg.yaml
    kubeadm alpha phase certs apiserver-etcd-client --config=/tmp/${HOST2}/kubeadmcfg.yaml
    cp -R /etc/kubernetes/pki /tmp/${HOST2}/
    # cleanup non-reusable certificates
    find /etc/kubernetes/pki -not -name ca.crt -not -name ca.key -type f -delete

    kubeadm alpha phase certs etcd-server --config=/tmp/${HOST1}/kubeadmcfg.yaml
    kubeadm alpha phase certs etcd-peer --config=/tmp/${HOST1}/kubeadmcfg.yaml
    kubeadm alpha phase certs etcd-healthcheck-client --config=/tmp/${HOST1}/kubeadmcfg.yaml
    kubeadm alpha phase certs apiserver-etcd-client --config=/tmp/${HOST1}/kubeadmcfg.yaml
    cp -R /etc/kubernetes/pki /tmp/${HOST1}/
    find /etc/kubernetes/pki -not -name ca.crt -not -name ca.key -type f -delete

    kubeadm alpha phase certs etcd-server --config=/tmp/${HOST0}/kubeadmcfg.yaml
    kubeadm alpha phase certs etcd-peer --config=/tmp/${HOST0}/kubeadmcfg.yaml
    kubeadm alpha phase certs etcd-healthcheck-client --config=/tmp/${HOST0}/kubeadmcfg.yaml
    kubeadm alpha phase certs apiserver-etcd-client --config=/tmp/${HOST0}/kubeadmcfg.yaml
    # No need to move the certs because they are for HOST0

    # clean up certs that should not be copied off this host
    find /tmp/${HOST2} -name ca.key -type f -delete
    find /tmp/${HOST1} -name ca.key -type f -delete
    ``` 
    -->
    ```sh
    kubeadm alpha phase certs etcd-server --config=/tmp/${HOST2}/kubeadmcfg.yaml
    kubeadm alpha phase certs etcd-peer --config=/tmp/${HOST2}/kubeadmcfg.yaml
    kubeadm alpha phase certs etcd-healthcheck-client --config=/tmp/${HOST2}/kubeadmcfg.yaml
    kubeadm alpha phase certs apiserver-etcd-client --config=/tmp/${HOST2}/kubeadmcfg.yaml
    cp -R /etc/kubernetes/pki /tmp/${HOST2}/
    # 清理不可重复使用的证书
    find /etc/kubernetes/pki -not -name ca.crt -not -name ca.key -type f -delete

    kubeadm alpha phase certs etcd-server --config=/tmp/${HOST1}/kubeadmcfg.yaml
    kubeadm alpha phase certs etcd-peer --config=/tmp/${HOST1}/kubeadmcfg.yaml
    kubeadm alpha phase certs etcd-healthcheck-client --config=/tmp/${HOST1}/kubeadmcfg.yaml
    kubeadm alpha phase certs apiserver-etcd-client --config=/tmp/${HOST1}/kubeadmcfg.yaml
    cp -R /etc/kubernetes/pki /tmp/${HOST1}/
    find /etc/kubernetes/pki -not -name ca.crt -not -name ca.key -type f -delete

    kubeadm alpha phase certs etcd-server --config=/tmp/${HOST0}/kubeadmcfg.yaml
    kubeadm alpha phase certs etcd-peer --config=/tmp/${HOST0}/kubeadmcfg.yaml
    kubeadm alpha phase certs etcd-healthcheck-client --config=/tmp/${HOST0}/kubeadmcfg.yaml
    kubeadm alpha phase certs apiserver-etcd-client --config=/tmp/${HOST0}/kubeadmcfg.yaml
    # 不需要移动 certs 因为它们是给 HOST0 使用的

    # 清理不应从此主机复制的证书
    find /tmp/${HOST2} -name ca.key -type f -delete
    find /tmp/${HOST1} -name ca.key -type f -delete
    ``` 

    <!--
    1.Copy certificates and kubeadm configs

        The certificates have been generated and now they must be moved to their
        respective hosts. 
    -->
1. 复制证书和 kubeadm 配置

    证书已生成，现在必须将它们移动到对应的主机。

    ```sh
    USER=ubuntu
    HOST=${HOST1}
    scp -r /tmp/${HOST}/* ${USER}@${HOST}:
    ssh ${USER}@${HOST}
    USER@HOST $ sudo -Es
    root@HOST $ chown -R root:root pki
    root@HOST $ mv pki /etc/kubernetes/
    ```

    <!--
    1.Ensure all expected files exist

        The complete list of required files on `$HOST0` is: 
    -->
1. 确保已经所有预期的文件都存在
   
    `$HOST0` 所需文件的完整列表如下：

    ```
    /tmp/${HOST0}
    └── kubeadmcfg.yaml
    ---
    /etc/kubernetes/pki
    ├── apiserver-etcd-client.crt
    ├── apiserver-etcd-client.key
    └── etcd
        ├── ca.crt
        ├── ca.key
        ├── healthcheck-client.crt
        ├── healthcheck-client.key
        ├── peer.crt
        ├── peer.key
        ├── server.crt
        └── server.key
    ```

    <!--
    On `$HOST1`: 
    -->
    在 `$HOST1`:

    ```
    $HOME
    └── kubeadmcfg.yaml
    ---
    /etc/kubernetes/pki
    ├── apiserver-etcd-client.crt
    ├── apiserver-etcd-client.key
    └── etcd
        ├── ca.crt
        ├── healthcheck-client.crt
        ├── healthcheck-client.key
        ├── peer.crt
        ├── peer.key
        ├── server.crt
        └── server.key
    ``` 

    <!--
    On `$HOST2` 
    -->
    在 `$HOST2`

    ```
    $HOME
    └── kubeadmcfg.yaml
    ---
    /etc/kubernetes/pki
    ├── apiserver-etcd-client.crt
    ├── apiserver-etcd-client.key
    └── etcd
        ├── ca.crt
        ├── healthcheck-client.crt
        ├── healthcheck-client.key
        ├── peer.crt
        ├── peer.key
        ├── server.crt
        └── server.key
    ``` 
    
    <!--
    1.Create the static pod manifests

        Now that the certificates and configs are in place it's time to create the
        manifests. On each host run the `kubeadm` command to generate a static manifest
        for etcd.
    -->
1. 创建静态 Pod 清单

    既然证书和配置已经就绪，是时候去创建清单了。在每台主机上运行 `kubeadm` 命令来生成 etcd 使用的静态清单。

    ```sh
    root@HOST0 $ kubeadm alpha phase etcd local --config=/tmp/${HOST0}/kubeadmcfg.yaml
    root@HOST1 $ kubeadm alpha phase etcd local --config=/home/ubuntu/kubeadmcfg.yaml
    root@HOST2 $ kubeadm alpha phase etcd local --config=/home/ubuntu/kubeadmcfg.yaml
    ``` 
   
    <!--
    1.Optional: Check the cluster health 
    -->
1. 可选：检查群集运行状况

    ```sh
    docker run --rm -it \
    --net host \
    -v /etc/kubernetes:/etc/kubernetes quay.io/coreos/etcd:v3.2.18 etcdctl \
    --cert-file /etc/kubernetes/pki/etcd/peer.crt \
    --key-file /etc/kubernetes/pki/etcd/peer.key \
    --ca-file /etc/kubernetes/pki/etcd/ca.crt \
    --endpoints https://${HOST0}:2379 cluster-health
    ...
    cluster is healthy
    ``` 

{{% /capture %}}

{{% capture whatsnext %}}

<!--
Once your have a working 3 member etcd cluster, you can continue setting up a
highly available control plane using the [external etcd method with
kubeadm](/docs/setup/independent/high-availability/). 
-->
一旦拥有了一个正常工作的 3 成员的 etcd 集群，你就可以基于[使用 kubeadm 的外部 etcd 方法](/docs/setup/independent/high-availability/)，继续部署一个高可用的控制平面。

{{% /capture %}}

